LTG/S3 event handler

This libray makes parsing LTG / S3 events trivial.

Look at examples on how to use it in:

• ltg.java.commons.ltg_event_handler for LTG events

• ltg.java.commons.phenomena_event_handler for old LTG events (still using XML, like it's 2001)

• ltg.java.commons.porcupine_event_handler for S3 events coming from https://github.com/educoder/PeacefulPorcupine